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040 The Role of Hair Cells in Hearing

Do you ever wonder what happens to the hair cells inside our ears as we hear sound? What role do these tiny hairs have in hearing?

Watch this short movie as Leslie explains clearly and vividly enough for us to understand the main role of these tiny hair cells as sound enters our ears.

Enjoy!

Transcript of Today’s Episode

Hello and welcome to another episode of Interactive Biology TV where we’re making Biology fun!  My name is Leslie Samuel and in this episode, Episode 40, I’m going to talk about the role of hair cells in hearing. So, let’s get right into it.

In Episode 39, we looked inside the cochlea to see what happened in response to sound. What we said was, in response to sound, the basilar membrane vibrated up and down, and this is the basilar membrane, which causes the Organ of Corti, which is this section here, to vibrate up and down, causing the tectorial membrane to move in a windshield wiper-like fashion that causes these hair cells to bend, the stereocilia, and the hair cells bend, causing a signal in the auditory nerve that then goes to the brain.  The brain says, “Okay that is sound,” and you hear it.

What we’re going to do today is we’re going to look specifically at what happens inside these hair cells, specially the inner hair cells which are directly responsible for the signal being sent to the brain that results in the sound that you are hearing.

So, let’s look at what happens inside those hair cells.  All right, so, I’m going to draw a hair cell.  Let’s say this is my hair cell right here. On the hair cell, I have stereocilia.  Now, this stereocilia occur in pairs: we have a long one and a short one.  In the short one, we have potassium channels so, that’s the potassium channel right here.   But, what’s interesting is that the long hair cell is mechanically connected to the short hair cell via that gate. Now, as you can imagine, when the tectorial membrane moves down on this hair cell, that causes the hair cell to bend.  So, let’s say this hair cell, the long hair cell, bends in that direction.  What is that going to do to these channels?  That’s going to cause these channels to open.  Now, these channels are mechanically-gated potassium channels.  They’re not extremely selective to potassium but, for this purpose, we’re going to look at what it does with the potassium ions.

Now, in the fluid that’s surrounding these stereocilia, we have endolymph. An endolymph is very rich in potassium ions.  So, let’s say we have potassium ions, K+, all around here.  When these mechanically-gated channels open, that is going to cause potassium ions to flow into the hair cells.  What is that going to do to the membrane potential (Em) ?  That is going to increase the membrane potential. Once the membrane potential increases, something else happens.  We have calcium ions that are also outside the cell. When that membrane potential increases, potassium is in here that’s going to cause calcium channels, voltage-gated calcium channels to open and calcium is going to rush into the cell.

Now, if you can remember when we spoke about neurotransmitter release, we said that calcium ions are the trigger that causes the neurotransmitter release in axon terminals.  This is the exact same thing that happens.  We have neurotransmitters in vesicles here and those neurotransmitters are then going to be released, and as I showed in the previous picture, this is connected to the auditory nerve, and that sends signals to the brain.

That’s all the content for this video.  I hope you learned a lot.  If you have any questions, go ahead and leave them in the comments below. That’s it for now, and I’ll see you in the next one.

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Leslie Samuel is the creator of Interactive Biology. His mission is to use this site to Make Biology fun for people all over the world.

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77 Responses to “040 The Role of Hair Cells in Hearing”

  1. naqqiya March 1, 2011 at 1:29 pm #

    Hi loved your video would also like to know about vestibular system.

    • Leslie March 2, 2011 at 11:00 pm #

      Hi Naqqiya,

      I don’t have a video explaining that at this point but here’s an article on Wikipedia that explains it very well. Hope that helps!

  2. MsPurplification March 28, 2011 at 6:48 pm #

    dude thanks for this. really helpful

  3. MsPurplification March 28, 2011 at 6:48 pm #

    dude thanks for this. really helpful

  4. InteractiveBiology March 28, 2011 at 10:00 pm #

    @MsPurplification Hey, thanks for the feedback. Glad you found value in it. Stay tuned for MANY more to come!

  5. InteractiveBiology March 28, 2011 at 10:00 pm #

    Hey, thanks for the feedback. Glad you found value in it. Stay tuned for MANY more to come!

  6. InteractiveBiology March 28, 2011 at 10:00 pm #

    Hey, thanks for the feedback. Glad you found value in it. Stay tuned for MANY more to come!

  7. MsPurplification March 28, 2011 at 10:48 pm #

    dude thanks for this. really helpful

  8. InteractiveBiology March 29, 2011 at 2:00 am #

    Hey, thanks for the feedback. Glad you found value in it. Stay tuned for MANY more to come!

  9. iason March 31, 2011 at 9:07 am #

    learning for a test from your videos :) thanks

    • Leslie March 31, 2011 at 9:37 am #

      You’re very much welcome. Glad they’re helping!

  10. katherinependragon April 13, 2011 at 12:57 am #

    These vids are great. Have you thought about making a vid about the pathway sound takes from Cranial nerve VIII to the auditory cortex? That’s the part that really confuses me!

  11. katherinependragon April 13, 2011 at 4:57 am #

    These vids are great. Have you thought about making a vid about the pathway sound takes from Cranial nerve VIII to the auditory cortex? That’s the part that really confuses me!

  12. InteractiveBiology April 13, 2011 at 6:17 am #

    @katherinependragon I actually haven’t looked at that process personally. Also, I’ve finished with the nervous system for now. Trying to get through a bunch of different topics in sequence. That might be something to look at the next time I go through the Nervous System in more detail, but that won’t be for a long while.

  13. InteractiveBiology April 13, 2011 at 6:17 am #

    I actually haven’t looked at that process personally. Also, I’ve finished with the nervous system for now. Trying to get through a bunch of different topics in sequence. That might be something to look at the next time I go through the Nervous System in more detail, but that won’t be for a long while.

  14. InteractiveBiology April 13, 2011 at 6:17 am #

    I actually haven’t looked at that process personally. Also, I’ve finished with the nervous system for now. Trying to get through a bunch of different topics in sequence. That might be something to look at the next time I go through the Nervous System in more detail, but that won’t be for a long while.

  15. InteractiveBiology April 13, 2011 at 10:17 am #

    I actually haven’t looked at that process personally. Also, I’ve finished with the nervous system for now. Trying to get through a bunch of different topics in sequence. That might be something to look at the next time I go through the Nervous System in more detail, but that won’t be for a long while.

  16. hayder August 29, 2011 at 6:53 pm #

    you are really make biology fun to me,you are not simple person,you are great

    • Lrsamuel August 30, 2011 at 9:53 am #

      I appreciate the feedback.

  17. Djalitana September 17, 2011 at 8:02 am #

    does the potassium channel opens because of the bending of the stereo cilia and has nothing to do with osmotic pressure? if enough potassium rush in why the cell need still calcium to rush into the cell? thank you very much.

  18. Djalitana September 17, 2011 at 12:02 pm #

    does the potassium channel opens because of the bending of the stereo cilia and has nothing to do with osmotic pressure? if enough potassium rush in why the cell need still calcium to rush into the cell? thank you very much.

  19. LittleDanzig November 12, 2011 at 5:53 pm #

    I’m learning a lot from these lessons! My teacher’s lectures + your lecture = better understanding! Don’t ever cease to strive for increasing your communication talent! Simplicity is key!

  20. LittleDanzig November 12, 2011 at 5:53 pm #

    I’m learning a lot from these lessons! My teacher’s lectures + your lecture = better understanding! Don’t ever cease to strive for increasing your communication talent! Simplicity is key!

  21. Eric Humphries November 12, 2011 at 10:53 pm #

    I’m learning a lot from these lessons! My teacher’s lectures + your lecture = better understanding! Don’t ever cease to strive for increasing your communication talent! Simplicity is key!

  22. Eric Humphries November 12, 2011 at 10:53 pm #

    I’m learning a lot from these lessons! My teacher’s lectures + your lecture = better understanding! Don’t ever cease to strive for increasing your communication talent! Simplicity is key!

  23. InteractiveBiology November 13, 2011 at 10:40 am #

    @LittleDanzig Thank you so much. We have more videos coming very soon, so please stay tuned!

  24. InteractiveBiology November 13, 2011 at 10:40 am #

    Thank you so much. We have more videos coming very soon, so please stay tuned!

  25. InteractiveBiology November 13, 2011 at 10:40 am #

    Thank you so much. We have more videos coming very soon, so please stay tuned!

  26. InteractiveBiology November 13, 2011 at 10:43 am #

    @Djalitana Thank you for your interest in our Biology videos. Unfortunately, Leslie is too busy at the moment to answer any Specific Biology questions. He has many to work on, so stay tuned for more.

  27. InteractiveBiology November 13, 2011 at 10:43 am #

    Thank you for your interest in our Biology videos. Unfortunately, Leslie is too busy at the moment to answer any Specific Biology questions. He has many to work on, so stay tuned for more.

  28. InteractiveBiology November 13, 2011 at 10:43 am #

    Thank you for your interest in our Biology videos. Unfortunately, Leslie is too busy at the moment to answer any Specific Biology questions. He has many to work on, so stay tuned for more.

  29. InteractiveBiology November 13, 2011 at 3:40 pm #

    Thank you so much. We have more videos coming very soon, so please stay tuned!

  30. InteractiveBiology November 13, 2011 at 3:43 pm #

    Thank you for your interest in our Biology videos. Unfortunately, Leslie is too busy at the moment to answer any Specific Biology questions. He has many to work on, so stay tuned for more.

  31. Djalitana November 13, 2011 at 5:25 pm #

    second watch answered my question, without calcium ions no neurotransmitter release. the ability of the hair cells in transmission of sound is varies according to their distance to the auditory nerve? thanks

  32. Djalitana November 13, 2011 at 10:25 pm #

    second watch answered my question, without calcium ions no neurotransmitter release. the ability of the hair cells in transmission of sound is varies according to their distance to the auditory nerve? thanks

  33. InteractiveBiology November 14, 2011 at 10:53 am #

    @Djalitana Unfortunately, Leslie is unavailable to take questions as he has no time to help. In the meantime, you can go to our FB fan page, post your questions, and your fellow readers, followers, and fellow enthusiasts in Biology may find time to answer them.

  34. InteractiveBiology November 14, 2011 at 10:53 am #

    Unfortunately, Leslie is unavailable to take questions as he has no time to help. In the meantime, you can go to our FB fan page, post your questions, and your fellow readers, followers, and fellow enthusiasts in Biology may find time to answer them.

  35. InteractiveBiology November 14, 2011 at 10:53 am #

    Unfortunately, Leslie is unavailable to take questions as he has no time to help. In the meantime, you can go to our FB fan page, post your questions, and your fellow readers, followers, and fellow enthusiasts in Biology may find time to answer them.

  36. InteractiveBiology November 14, 2011 at 3:53 pm #

    Unfortunately, Leslie is unavailable to take questions as he has no time to help. In the meantime, you can go to our FB fan page, post your questions, and your fellow readers, followers, and fellow enthusiasts in Biology may find time to answer them.

  37. 215196 February 9, 2012 at 12:39 am #

    can you tell me what is the different between inner hair cell and outer hair cell?

  38. 215196 February 9, 2012 at 5:39 am #

    can you tell me what is the different between inner hair cell and outer hair cell?

  39. 20019988 February 15, 2012 at 2:27 pm #

    Great video very simple illustration

  40. 20019988 February 15, 2012 at 7:27 pm #

    Great video very simple illustration

  41. rita silva March 18, 2012 at 11:43 am #

    Is this the last video on audition?

  42. rita silva March 18, 2012 at 11:43 am #

    Is this the last video on audition?

  43. Anonymous March 18, 2012 at 3:43 pm #

    Is this the last video on audition?

  44. Anonymous March 18, 2012 at 3:43 pm #

    Is this the last video on audition?

  45. rita silva March 18, 2012 at 3:43 pm #

    Is this the last video on audition?

  46. ilselpz April 18, 2012 at 1:43 am #

    sir i love you. i think i am finally getting this !

  47. ilselpz April 18, 2012 at 5:43 am #

    sir i love you. i think i am finally getting this !

  48. Adriana May 5, 2012 at 10:00 pm #

    loved it, it would be good if you did something about vestibular system too. from Portugal!

    • Leslie Samuel May 7, 2012 at 5:03 pm #

      Hi, I’d love to but unfortunately I’m no longer able to take different requests.

  49. SpeedySpod May 12, 2012 at 7:42 am #

    what’s the neurotransmitter? Possibly glutamate and ‘unknown substance’ – would you happen to know???

  50. SpeedySpod May 12, 2012 at 7:42 am #

    what’s the neurotransmitter? Possibly glutamate and ‘unknown substance’ – would you happen to know???

  51. SpeedySpod May 12, 2012 at 7:42 am #

    what’s the neurotransmitter? Possibly glutamate and ‘unknown substance’ – would you happen to know???

  52. kmac0258 May 20, 2012 at 2:18 am #

    I really enjoy these and they really help me to learn. is there a possibility of him continuing the senses and doing taste and smell too?

  53. kmac0258 May 20, 2012 at 2:18 am #

    I really enjoy these and they really help me to learn. is there a possibility of him continuing the senses and doing taste and smell too?

  54. deathstarXslaughter June 10, 2012 at 6:14 am #

    thank you!!!!!! :)

  55. deathstarXslaughter June 10, 2012 at 6:14 am #

    thank you!!!!!! :)

  56. green5sing June 20, 2012 at 5:11 pm #

    Thank you so much! I was so lost in my Audiology class until I watched your videos (36-40)! You do such an awesome job of explaining things so that people can understand it!

  57. green5sing June 20, 2012 at 5:11 pm #

    Thank you so much! I was so lost in my Audiology class until I watched your videos (36-40)! You do such an awesome job of explaining things so that people can understand it!

  58. green5sing June 20, 2012 at 5:11 pm #

    Thank you so much! I was so lost in my Audiology class until I watched your videos (36-40)! You do such an awesome job of explaining things so that people can understand it!

  59. TshegoTT July 24, 2012 at 9:48 am #

    Thank you very much for the video. Please make a video on the relation between the outer hair cells and otoacoustic emissions (or just the generation of otoacoustic emissions in general). Thank you.

  60. TshegoTT July 24, 2012 at 9:48 am #

    Thank you very much for the video. Please make a video on the relation between the outer hair cells and otoacoustic emissions (or just the generation of otoacoustic emissions in general). Thank you.

  61. TshegoTT July 24, 2012 at 9:50 am #

    Does anyone know where I can get a video/article which clearly explains how outer hair cells help generate otoacoustic emissions (OAEs) and/or how the reflection of incoming waves occur? Thank you.

  62. TshegoTT July 24, 2012 at 9:50 am #

    Does anyone know where I can get a video/article which clearly explains how outer hair cells help generate otoacoustic emissions (OAEs) and/or how the reflection of incoming waves occur? Thank you.

  63. rmalinak07 July 28, 2012 at 11:48 pm #

    These were the most helpful series of videos on the subject on youtube. thank you!

  64. the7real7deal October 1, 2012 at 1:39 pm #

    The best series of Anatomy and Physiology videos on the internet.

  65. scarletwomannedm October 23, 2012 at 6:46 pm #

    As a student getting ready to take my state board exam for Cosmetology this is a fascinating mini-lecture. All of your videos have helped me to understand anatomy and biology better (especially the parts on the Integumentary System–which for the Cosmetology field is obviously the most important to be studying and understanding) They have kept me interested and you made it fun! Great job!!

  66. Domsmudge December 31, 2012 at 2:03 pm #

    Really helpful, thanks!

  67. Simon Bray February 11, 2013 at 9:02 pm #

    legend!

  68. Kin Shek February 25, 2013 at 12:45 pm #

    Uhhjj

  69. Kin Shek February 25, 2013 at 12:50 pm #

    As a patient of labyrinthitis, been dizzy for 24/7 for a year Now. Could you explain the hair cells in semi circular canals and the importance for balance and sense of space. Thx

  70. István Farbaky May 27, 2013 at 12:24 pm #

    do you have any video about the eye?

  71. Sreelakshmi V A July 8, 2013 at 2:46 am #

    Can you explain what happens in tectorial membrane in response to the vibrations in organ of corti???

  72. Leeann Gooding July 29, 2013 at 6:45 am #

    omg thank you so much for this video….i kept reading that k+ gates open and cell is depolarized and i couldnt understand why but its because endolymph is rich in K+ so gradient is higher outside cell ….thank you thank you

  73. dinusha manathunge October 29, 2013 at 6:39 am #

    more helpful series of videos.